Thas grant encompasses several areas of investigation. One deals with the controlling factors of normal and abnormal adolescent sexual development in both humans and animals. Another deals with the production, release, and action of pituitary tropic hormones. Therefore, the application is divided into 3 separate but interlinking presentations. 1. Studies pertaining to to adolescent sexual development in the human, which will include the effect of human LH onadrenal androgen production, (b) testicular tubular maturation in mormal adolescent males, (c) the onset and etiology of gonadal failure in myotonia dystrophica patients, (d) the role of GH in maturation of spermatogonia, and others (see application). 2. Studies pertaining to adolescent sexual development in the animal model will utilize a constant I.V. infusion techniqque and a chronic venous catheterization technique (both developed by R.S.) to elucidate the plus and minus feedback inter-relationships between the sex steroids and gonadotropin release in preadolescent, adolescent, andpost-adolescent rats. 3. Studies regarding the production and action o GH and other hormones will include (a) the effect of acute and prolonged prostoglandin administration on the release of GH, LH, FSH, TSH, prolactin, glucagon, and insulin, (b) the role and interrelationship of the adrenergic system and releasing factors on the release of various pituitary hormones, (c) the inter-relation of thyroxin and the metabolic clearance ofprolactin and TSH release by TRF, (d) the therapeutic effect of HGH in intruterine dwarfism and Crohn's disease.